A light emitting device may have, for example, a light emitting diode. The light emitting diode, which is a kind of a semiconductor device for converting electrical energy into light, has been spotlighted as a next generation light source in substitution for a conventional phosphor lamp and a glow lamp.
Since the light emitting diode generates the light by using the semiconductor device, the light emitting diode may represent significantly low power consumption as compared with the glow lamp that generates the light by heating tungsten or the phosphor lamp that generates the light by urging ultraviolet ray, which is generated through the high-voltage discharge, to collide with a phosphor substance.
In addition, since the light emitting diode generates the light by using the potential gap of the semiconductor device, the light emitting diode represents a longer lifespan, a rapider response characteristic, and a more eco-friendly feature as compared with those of a conventional light source.
In this regard, various studies and researches have been performed to substitute the conventional light source with the light emitting diode. The light emitting diode is increasingly used as light sources for lighting devices, such as various lamps used indoors and outdoors, liquid crystal displays, electric signboards, and street lamps.